The effects of repeated oral stimulation on ingestive responding were
investigated in adult rats. A series of brief intraoral infusions of f
lavored diet was delivered to female rats once every minute through an
oral cannula. When the flavor of the infused diet remained constant,
significant decreases in mouthing behavior were observed by the end of
testing, whereas switching the flavor of the diet during testing resu
lted in enhanced responding and infusions delivered through gastric ca
nnulas produced minimal effects. Patterns of oral responding were also
similar in food-restricted rats. These patterns of responding suggest
that adult rats habituate to oral stimulation. Finally, oral habituat
ion led to decreased ingestion, whereas gastric infusions had minimal
effects. Thus, oral habituation may represent a mechanism influencing
intake in rats at all ages.